Process of producing pure copper.



No. 782,145. PATENTED FEB. 7, 1905. L. M. LAFQNTAINE.

PRUGESS 0F PRODUGING PURE COPPER.

APPLICATION IILED SEPT. 12, 1903.

' 2 SHEETS-SHEET l.

PATBNTED PEB. 7, 1905.

L. M. LAFONTAINE.

PROCESS OP PRODUGING PURE COPPER.

APPLIUATION FILED SEPT. 12, 1903.

2 SHEETS-SHEET 2.

s l s R W www UNITED STATES Patented February 7, 1905.

PATENT @ENCEc LOUIS MAURICE LAFONTAINE, OF PARIS, FRANCE.

SPECIFICATION forming part of Letters Patent No. 782,145, dated February '7, 1905.

Application iiled September 12, 1903. Serial No. 172,861.

T0 all whom it 'nm/1J concern:

Be it known that l, Louis MAURICE LAFON- TAINE, a citizen of the French Republic, and a resident of Paris, France, have invented ce1'- tain new and useful Improvements in Processes of Producing' Pure Copper, of which the following' is a specification.

This invention relates more particularly to processes for refining copper and obtaining chemically pure electrolytic copper from copperores, scrap-copper, and coppersulfate. lts objects are to produce a chemically-pure copper from the various sources of copper hereinbefore mentioned; and it consists in the various operations which will be fully described hereinafter.

In' view of the numerous advantages of chemically-pure copper a means has been sought for its economical productions, and this result is obtained by the present process, which consists, mainly, in reducing the pure copper from the various sources of copper in an electrolytic vat comprising several electrodes coupled in tension, in which vat is a sulfatic solution which preferably remains of constant density during electrolytic action. The arrangement of the vat and the composition of the electrolytic bath allow of obtaining' in a sing'le operation quantities of pure copper which cannot be obtained by known processes without the use of a larger amount of material, more space, and greater manual labor in proportion tothe results obtained.

In order to render this invention more clear, reference is made tothe accompanying drawings, in which-- Figure l shows a plan View of the vat with several elements connected in parallel, but which might otherwise be connected in series. Fig. 2 is a longitudinal sectional view through a vat, illustrating certain features of this invention. Fig. 3 is a cross-sectional view of the same. Fig. s is a sectional view showing a plate of copper cast in the center of the agglomerate.

A represents the vat proper, in which are located the anodes a, which are connected together by a strip C, in connection with a source of electricity, and anodes c, which are connected together by a strip I), which is connected with the opposite pole of the electrical source. A soluble anode is preferably used; butl I also use an insoluble anode, according to whether copper ores or waste copper is treated; but in either ease the waste or scrap copper, as also the ores containing' quantities of impurities, which should not be brought into contact with the cathodes, receiving the deposit of pure copper.

In a lead-lined vat of any desired capacity is put a bath composed of liltercd or rain water and sulfate of copper. The latter should be free from iron or other matters. lVhen the water is completely saturated, there is added to the solution for each liter of the same eight to ten centiliters of pure sulfuric acid, which immediately forms a precipitate. The solution becomes clear and takes the highly-characteristic green-blue tint. This solution is then decanted or filtered in order t0 remove therefrom suspended or precipitated matters, and about one kilogram of calcinedsoot, commonly known as lampblack, is added thereto for cach tive hundred liters of the solution. This addition of calcined soot has for its object to season the bath to allow of obtaining a more regular and dense deposit. 'lhe use of a quantity of calcined soot or lampblaek for seasoning the bath gives to the latter a greater conductibility and a facility for depositing at the athode a more dense and homogeneous layer of copper. lVllen used in large quantities, it is preferable to prepare this solution in special vats and draw it oli' into the electrolytic vat as needed. A soluble anode is placed in this bath, said anode being formed of the matters to be treatedsuch as ores, pyrites, rnattes, concentrates, waste ot' raw copper, and the like-ein the following' manner: For copper ores or pyrites the anode is formed by constructing a compartment between two perforated partitions B, having a closed bottom and ends 7)', as shown in Figs. 2 and 3, of wood or other material not readily affected by the acids or the electric current, said compartment being adapted to receive from live hundred to one thousand kilograms of ore, according to the size of the electrolytic vat used. In the cen- IOO ter of the compartment is arranged a plate of raw copper of one-half to one centimeter in Y thickness and covering a surface equal to twothirds of the breadth and height of the vat. This plate is connected with the positive pole of the battery. The ore or pyrites, which have previously been crushed into as small particles as possible, is introduced into the. compartment on both sides of the copper plate to form as compact a mass as possible.

The mattes are readily prepared for use as anodes by casting them in suitable-size plates for the vat used. The difficulty in preparing concentrates or dust for anodes lies in agglomerating the particles to form plates. This is done by preparing a bath of concentrated quicklime, and when thelime is slaked a certain quantity of concentrate in the proportion of seventy per cent. of concentrate to thirty per cent. of lime is gradually introduced,the mass being stirred accordingly as the concentrate is added in order to form a paste or mortar. The object of this agglomeration is to enable the dust of whatever nature produced by the pyrites and ores to be utilized, said dust or powder containing from twentyfive per cent. to thirty-five per cent. of copper. This agglomeration allows of utilizing them without roasting and to transport them from the place where they were extracted. The lime, protoXid of calcium, CaO, used has for its object to serve as an agglomerant, for which purpose it is preferably used on account of its porosity, as it does not prevent the action of the current. Moreover, when coming into contact with the acid of the bath it becomes practically insoluble, the sulfuric acid transforming the protoXid of calcium into bisulfuret of calcium GaSz, which is very slightly soluble in water. Consequently the concentrates agglomerated with the lime can be transformed into sulfate of copper until they are completely eXhaused without danger of disaggregation of the agglomerated anode. This mass is molded in rectangular molds of four to five centimeters in thickness and corresponding in surface to the size of the vat. The mass in each mold is compressed by means of movable cast rollers, which are passed over the molds, and afterward the mass is allowed to dry eitherl in the open air or in a dryingfurnace. When thus prepared, the plates of agglomerate are arranged in the vat in a similar manner to the arrangement for ores by being placed on either side of the plate forming the anode.

It will be apparent that the plate of raw copper may be cast in the center of the agglomerate, as shown at E, Fig. 4. This arrangement would have the advantage of dispensing with the copper plates in the vat and each plate of concentrate would form an a-node, which is easily replaced in proportion as it is worn out.

Waste copper, such as turnings or filings,

may also be treated by the present processes by arranging the said turnings and filings or dust, which have previously been compressed, in the same way that the ore is treated, with the difference, however, that it is not necessary to have a copper plate for forming the anode, as the waste copper may be directly connected with the positive pole. Y

The cathode is always formed of a` thin plate of pure copper of one-half to one millimeter in thickness and having a surface corresponding to the anode.

In place of constructing a simple vat associated in series, which requires a large place for a relatively small production, as has hitherto been done, better results are obtained by using only one vat of desired size containing several electrodes in the same bath, which are connected in tension. This arrangement is also of very great importance, as it greatly re.- duces the resistance to be overcome, and it is evident that the electric current, having only to pass through one bath with electrodes of large surfaces, will meet with less resistance than if it had to pass through several baths arranged in series with electrodes in proportion. A

It is obvious that any suitable electric regulating device may be used for regulating the current sent through the vat. I arrange in the circuit of the current an ampere-meter which has for its object to indicate at eachl moment the density of the current; also, a rheostat, the object of which is to vary the resistance of the circuit, and thus regulate the density of the current according to the nature and surface of the electrodes; also, a current-breaker, which has for its object to prevent changes in the direction of the current which might arise on account of the polarization of the electrodes in the vat. However, as these are common forms of electrical instruments and form no part of this invention, they have been omitted from the drawings. The current produces on the cathode a constantly-increasing deposit of pure metal, while the anode is progressively dissolved. The metals united with the copper act in different manners according to their nature. /Vhen the impurity consists of lead in large quantity. the lead remains insoluble in the electrolytic liquid and is not attacked, the copper alone being dissolved and deposited at the negative pole. If the lead occurs in small quantity, it falls in the form of dust to the bottom of the vat, as is also the case with the chlorides of calcium which is used to agglomerate the concentrates. In treating argentif- In proportion as the lOO I'Io

electric current passes the copper of the anode is dissolved in the suliate-of-copper bath, thus maintaining' its density, and the pure metal is transferred to the thin plate, forming the cathode, the impurities falling to the bottom of the vat.

Having thus described my invention, what I claim ish 1. A process for producing pure copper, which consists in forming the copper-producing ores into suitable plates tor anodes without previouslyv treating the ores, and subjecting said plates to an electrolytic bath whereby an electric current causes dissolution ot' the copper in said plates and .transfers it to the cathodes ot' the cell.

A process for reiiningcopper, which consists in Vforming the copper-producing substances into plates, inserting said plates with suitable cathode-plates into an electrolytic bath, which has previously been prepared by saturating water with sulfate ot' copper, then adding to the same a quantity of sulfuric acid, then tiltering the liquid and adding, calcined soot thereto, and directing a current ot' electricity through the cell thus formed.

3. A process of producing chemically-pure copper, which consists in connecting a series ot' plates formed from the copper-producing material in an electrolytic bath providing a number ot' cathode-plates also connected in series to coact with said iirst-named plates, said bath being composed of a solution ot' sulfate of copper t0 which has been added calcined soot, then directing a current of electricity through the electric cell thus formed whereby the copper will be dissolved troni the copperproducing material and deposited on the cathodes, substantially as described.

4. A process for producing copper which consists in agglomerating the copper-producing material with lime forming plates from,

the agglomerate, said plates being adapted to serve as soluble anodes and subjecting said plates to the action of an electric current and to the action ot' an electrolyte in which there is also placed a suitable cathode whereby the copper will be reduced and deposited on the cathode, substantially as described.

5,. An electrolytic process for producing copper which consists in subjectingl a soluble anode-plate formed of the copper-producing material without previous treatment to an electric current in a solution which remains ot' constant density by dissolving the copper from the soluble anode whereby the metal is first transformed into a salt and then recovered from the salt as pure metal on the cathode, substantially as described.

ln testimony whereotI l atlix my signature in presence ot' two witnesses.

LOUIS MAURICE LAlfONTAINE.

\\"itnesses:

AUGUs'rUs E. INGRAM, PAUL F. PQUE'r. 

